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1/*
2 * cdc-wdm.c
3 *
4 * This driver supports USB CDC WCM Device Management.
5 *
6 * Copyright (c) 2007-2009 Oliver Neukum
7 *
8 * Some code taken from cdc-acm.c
9 *
10 * Released under the GPLv2.
11 *
12 * Many thanks to Carl Nordbeck
13 */
14#include <linux/kernel.h>
15#include <linux/errno.h>
16#include <linux/slab.h>
17#include <linux/module.h>
18#include <linux/mutex.h>
19#include <linux/uaccess.h>
20#include <linux/bitops.h>
21#include <linux/poll.h>
22#include <linux/usb.h>
23#include <linux/usb/cdc.h>
24#include <asm/byteorder.h>
25#include <asm/unaligned.h>
26#include <linux/usb/cdc-wdm.h>
27
28/*
29 * Version Information
30 */
31#define DRIVER_VERSION "v0.03"
32#define DRIVER_AUTHOR "Oliver Neukum"
33#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
34
35#define HUAWEI_VENDOR_ID 0x12D1
36
37static const struct usb_device_id wdm_ids[] = {
38 {
39 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
40 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
41 .bInterfaceClass = USB_CLASS_COMM,
42 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
43 },
44 {
45 /*
46 * Huawei E392, E398 and possibly other Qualcomm based modems
47 * embed the Qualcomm QMI protocol inside CDC on CDC ECM like
48 * control interfaces. Userspace access to this is required
49 * to configure the accompanying data interface
50 */
51 .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
52 USB_DEVICE_ID_MATCH_INT_INFO,
53 .idVendor = HUAWEI_VENDOR_ID,
54 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
55 .bInterfaceSubClass = 1,
56 .bInterfaceProtocol = 9, /* NOTE: CDC ECM control interface! */
57 },
58 {
59 /* Vodafone/Huawei K5005 (12d1:14c8) and similar modems */
60 .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
61 USB_DEVICE_ID_MATCH_INT_INFO,
62 .idVendor = HUAWEI_VENDOR_ID,
63 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
64 .bInterfaceSubClass = 1,
65 .bInterfaceProtocol = 57, /* NOTE: CDC ECM control interface! */
66 },
67 { }
68};
69
70MODULE_DEVICE_TABLE (usb, wdm_ids);
71
72#define WDM_MINOR_BASE 176
73
74
75#define WDM_IN_USE 1
76#define WDM_DISCONNECTING 2
77#define WDM_RESULT 3
78#define WDM_READ 4
79#define WDM_INT_STALL 5
80#define WDM_POLL_RUNNING 6
81#define WDM_RESPONDING 7
82#define WDM_SUSPENDING 8
83#define WDM_RESETTING 9
84
85#define WDM_MAX 16
86
87/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
88#define WDM_DEFAULT_BUFSIZE 256
89
90static DEFINE_MUTEX(wdm_mutex);
91static DEFINE_SPINLOCK(wdm_device_list_lock);
92static LIST_HEAD(wdm_device_list);
93
94/* --- method tables --- */
95
96struct wdm_device {
97 u8 *inbuf; /* buffer for response */
98 u8 *outbuf; /* buffer for command */
99 u8 *sbuf; /* buffer for status */
100 u8 *ubuf; /* buffer for copy to user space */
101
102 struct urb *command;
103 struct urb *response;
104 struct urb *validity;
105 struct usb_interface *intf;
106 struct usb_ctrlrequest *orq;
107 struct usb_ctrlrequest *irq;
108 spinlock_t iuspin;
109
110 unsigned long flags;
111 u16 bufsize;
112 u16 wMaxCommand;
113 u16 wMaxPacketSize;
114 __le16 inum;
115 int reslength;
116 int length;
117 int read;
118 int count;
119 dma_addr_t shandle;
120 dma_addr_t ihandle;
121 struct mutex wlock;
122 struct mutex rlock;
123 wait_queue_head_t wait;
124 struct work_struct rxwork;
125 int werr;
126 int rerr;
127
128 struct list_head device_list;
129 int (*manage_power)(struct usb_interface *, int);
130};
131
132static struct usb_driver wdm_driver;
133
134/* return intfdata if we own the interface, else look up intf in the list */
135static struct wdm_device *wdm_find_device(struct usb_interface *intf)
136{
137 struct wdm_device *desc;
138
139 spin_lock(&wdm_device_list_lock);
140 list_for_each_entry(desc, &wdm_device_list, device_list)
141 if (desc->intf == intf)
142 goto found;
143 desc = NULL;
144found:
145 spin_unlock(&wdm_device_list_lock);
146
147 return desc;
148}
149
150static struct wdm_device *wdm_find_device_by_minor(int minor)
151{
152 struct wdm_device *desc;
153
154 spin_lock(&wdm_device_list_lock);
155 list_for_each_entry(desc, &wdm_device_list, device_list)
156 if (desc->intf->minor == minor)
157 goto found;
158 desc = NULL;
159found:
160 spin_unlock(&wdm_device_list_lock);
161
162 return desc;
163}
164
165/* --- callbacks --- */
166static void wdm_out_callback(struct urb *urb)
167{
168 struct wdm_device *desc;
169 desc = urb->context;
170 spin_lock(&desc->iuspin);
171 desc->werr = urb->status;
172 spin_unlock(&desc->iuspin);
173 kfree(desc->outbuf);
174 desc->outbuf = NULL;
175 clear_bit(WDM_IN_USE, &desc->flags);
176 wake_up(&desc->wait);
177}
178
179static void wdm_in_callback(struct urb *urb)
180{
181 struct wdm_device *desc = urb->context;
182 int status = urb->status;
183
184 spin_lock(&desc->iuspin);
185 clear_bit(WDM_RESPONDING, &desc->flags);
186
187 if (status) {
188 switch (status) {
189 case -ENOENT:
190 dev_dbg(&desc->intf->dev,
191 "nonzero urb status received: -ENOENT");
192 goto skip_error;
193 case -ECONNRESET:
194 dev_dbg(&desc->intf->dev,
195 "nonzero urb status received: -ECONNRESET");
196 goto skip_error;
197 case -ESHUTDOWN:
198 dev_dbg(&desc->intf->dev,
199 "nonzero urb status received: -ESHUTDOWN");
200 goto skip_error;
201 case -EPIPE:
202 dev_err(&desc->intf->dev,
203 "nonzero urb status received: -EPIPE\n");
204 break;
205 default:
206 dev_err(&desc->intf->dev,
207 "Unexpected error %d\n", status);
208 break;
209 }
210 }
211
212 desc->rerr = status;
213 desc->reslength = urb->actual_length;
214 memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
215 desc->length += desc->reslength;
216skip_error:
217 wake_up(&desc->wait);
218
219 set_bit(WDM_READ, &desc->flags);
220 spin_unlock(&desc->iuspin);
221}
222
223static void wdm_int_callback(struct urb *urb)
224{
225 int rv = 0;
226 int status = urb->status;
227 struct wdm_device *desc;
228 struct usb_cdc_notification *dr;
229
230 desc = urb->context;
231 dr = (struct usb_cdc_notification *)desc->sbuf;
232
233 if (status) {
234 switch (status) {
235 case -ESHUTDOWN:
236 case -ENOENT:
237 case -ECONNRESET:
238 return; /* unplug */
239 case -EPIPE:
240 set_bit(WDM_INT_STALL, &desc->flags);
241 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
242 goto sw; /* halt is cleared in work */
243 default:
244 dev_err(&desc->intf->dev,
245 "nonzero urb status received: %d\n", status);
246 break;
247 }
248 }
249
250 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
251 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
252 urb->actual_length);
253 goto exit;
254 }
255
256 switch (dr->bNotificationType) {
257 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
258 dev_dbg(&desc->intf->dev,
259 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
260 dr->wIndex, dr->wLength);
261 break;
262
263 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
264
265 dev_dbg(&desc->intf->dev,
266 "NOTIFY_NETWORK_CONNECTION %s network",
267 dr->wValue ? "connected to" : "disconnected from");
268 goto exit;
269 default:
270 clear_bit(WDM_POLL_RUNNING, &desc->flags);
271 dev_err(&desc->intf->dev,
272 "unknown notification %d received: index %d len %d\n",
273 dr->bNotificationType, dr->wIndex, dr->wLength);
274 goto exit;
275 }
276
277 spin_lock(&desc->iuspin);
278 clear_bit(WDM_READ, &desc->flags);
279 set_bit(WDM_RESPONDING, &desc->flags);
280 if (!test_bit(WDM_DISCONNECTING, &desc->flags)
281 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
282 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
283 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
284 __func__, rv);
285 }
286 spin_unlock(&desc->iuspin);
287 if (rv < 0) {
288 clear_bit(WDM_RESPONDING, &desc->flags);
289 if (rv == -EPERM)
290 return;
291 if (rv == -ENOMEM) {
292sw:
293 rv = schedule_work(&desc->rxwork);
294 if (rv)
295 dev_err(&desc->intf->dev,
296 "Cannot schedule work\n");
297 }
298 }
299exit:
300 rv = usb_submit_urb(urb, GFP_ATOMIC);
301 if (rv)
302 dev_err(&desc->intf->dev,
303 "%s - usb_submit_urb failed with result %d\n",
304 __func__, rv);
305
306}
307
308static void kill_urbs(struct wdm_device *desc)
309{
310 /* the order here is essential */
311 usb_kill_urb(desc->command);
312 usb_kill_urb(desc->validity);
313 usb_kill_urb(desc->response);
314}
315
316static void free_urbs(struct wdm_device *desc)
317{
318 usb_free_urb(desc->validity);
319 usb_free_urb(desc->response);
320 usb_free_urb(desc->command);
321}
322
323static void cleanup(struct wdm_device *desc)
324{
325 kfree(desc->sbuf);
326 kfree(desc->inbuf);
327 kfree(desc->orq);
328 kfree(desc->irq);
329 kfree(desc->ubuf);
330 free_urbs(desc);
331 kfree(desc);
332}
333
334static ssize_t wdm_write
335(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
336{
337 u8 *buf;
338 int rv = -EMSGSIZE, r, we;
339 struct wdm_device *desc = file->private_data;
340 struct usb_ctrlrequest *req;
341
342 if (count > desc->wMaxCommand)
343 count = desc->wMaxCommand;
344
345 spin_lock_irq(&desc->iuspin);
346 we = desc->werr;
347 desc->werr = 0;
348 spin_unlock_irq(&desc->iuspin);
349 if (we < 0)
350 return -EIO;
351
352 buf = kmalloc(count, GFP_KERNEL);
353 if (!buf) {
354 rv = -ENOMEM;
355 goto outnl;
356 }
357
358 r = copy_from_user(buf, buffer, count);
359 if (r > 0) {
360 kfree(buf);
361 rv = -EFAULT;
362 goto outnl;
363 }
364
365 /* concurrent writes and disconnect */
366 r = mutex_lock_interruptible(&desc->wlock);
367 rv = -ERESTARTSYS;
368 if (r) {
369 kfree(buf);
370 goto outnl;
371 }
372
373 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
374 kfree(buf);
375 rv = -ENODEV;
376 goto outnp;
377 }
378
379 r = usb_autopm_get_interface(desc->intf);
380 if (r < 0) {
381 kfree(buf);
382 rv = usb_translate_errors(r);
383 goto outnp;
384 }
385
386 if (!(file->f_flags & O_NONBLOCK))
387 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
388 &desc->flags));
389 else
390 if (test_bit(WDM_IN_USE, &desc->flags))
391 r = -EAGAIN;
392
393 if (test_bit(WDM_RESETTING, &desc->flags))
394 r = -EIO;
395
396 if (r < 0) {
397 kfree(buf);
398 rv = r;
399 goto out;
400 }
401
402 req = desc->orq;
403 usb_fill_control_urb(
404 desc->command,
405 interface_to_usbdev(desc->intf),
406 /* using common endpoint 0 */
407 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
408 (unsigned char *)req,
409 buf,
410 count,
411 wdm_out_callback,
412 desc
413 );
414
415 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
416 USB_RECIP_INTERFACE);
417 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
418 req->wValue = 0;
419 req->wIndex = desc->inum;
420 req->wLength = cpu_to_le16(count);
421 set_bit(WDM_IN_USE, &desc->flags);
422 desc->outbuf = buf;
423
424 rv = usb_submit_urb(desc->command, GFP_KERNEL);
425 if (rv < 0) {
426 kfree(buf);
427 desc->outbuf = NULL;
428 clear_bit(WDM_IN_USE, &desc->flags);
429 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
430 rv = usb_translate_errors(rv);
431 } else {
432 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
433 req->wIndex);
434 }
435out:
436 usb_autopm_put_interface(desc->intf);
437outnp:
438 mutex_unlock(&desc->wlock);
439outnl:
440 return rv < 0 ? rv : count;
441}
442
443static ssize_t wdm_read
444(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
445{
446 int rv, cntr;
447 int i = 0;
448 struct wdm_device *desc = file->private_data;
449
450
451 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
452 if (rv < 0)
453 return -ERESTARTSYS;
454
455 cntr = ACCESS_ONCE(desc->length);
456 if (cntr == 0) {
457 desc->read = 0;
458retry:
459 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
460 rv = -ENODEV;
461 goto err;
462 }
463 i++;
464 if (file->f_flags & O_NONBLOCK) {
465 if (!test_bit(WDM_READ, &desc->flags)) {
466 rv = cntr ? cntr : -EAGAIN;
467 goto err;
468 }
469 rv = 0;
470 } else {
471 rv = wait_event_interruptible(desc->wait,
472 test_bit(WDM_READ, &desc->flags));
473 }
474
475 /* may have happened while we slept */
476 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
477 rv = -ENODEV;
478 goto err;
479 }
480 if (test_bit(WDM_RESETTING, &desc->flags)) {
481 rv = -EIO;
482 goto err;
483 }
484 usb_mark_last_busy(interface_to_usbdev(desc->intf));
485 if (rv < 0) {
486 rv = -ERESTARTSYS;
487 goto err;
488 }
489
490 spin_lock_irq(&desc->iuspin);
491
492 if (desc->rerr) { /* read completed, error happened */
493 desc->rerr = 0;
494 spin_unlock_irq(&desc->iuspin);
495 rv = -EIO;
496 goto err;
497 }
498 /*
499 * recheck whether we've lost the race
500 * against the completion handler
501 */
502 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
503 spin_unlock_irq(&desc->iuspin);
504 goto retry;
505 }
506 if (!desc->reslength) { /* zero length read */
507 dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
508 clear_bit(WDM_READ, &desc->flags);
509 spin_unlock_irq(&desc->iuspin);
510 goto retry;
511 }
512 cntr = desc->length;
513 spin_unlock_irq(&desc->iuspin);
514 }
515
516 if (cntr > count)
517 cntr = count;
518 rv = copy_to_user(buffer, desc->ubuf, cntr);
519 if (rv > 0) {
520 rv = -EFAULT;
521 goto err;
522 }
523
524 spin_lock_irq(&desc->iuspin);
525
526 for (i = 0; i < desc->length - cntr; i++)
527 desc->ubuf[i] = desc->ubuf[i + cntr];
528
529 desc->length -= cntr;
530 /* in case we had outstanding data */
531 if (!desc->length)
532 clear_bit(WDM_READ, &desc->flags);
533
534 spin_unlock_irq(&desc->iuspin);
535
536 rv = cntr;
537
538err:
539 mutex_unlock(&desc->rlock);
540 return rv;
541}
542
543static int wdm_flush(struct file *file, fl_owner_t id)
544{
545 struct wdm_device *desc = file->private_data;
546
547 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
548
549 /* cannot dereference desc->intf if WDM_DISCONNECTING */
550 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
551 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
552 desc->werr);
553
554 return usb_translate_errors(desc->werr);
555}
556
557static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
558{
559 struct wdm_device *desc = file->private_data;
560 unsigned long flags;
561 unsigned int mask = 0;
562
563 spin_lock_irqsave(&desc->iuspin, flags);
564 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
565 mask = POLLHUP | POLLERR;
566 spin_unlock_irqrestore(&desc->iuspin, flags);
567 goto desc_out;
568 }
569 if (test_bit(WDM_READ, &desc->flags))
570 mask = POLLIN | POLLRDNORM;
571 if (desc->rerr || desc->werr)
572 mask |= POLLERR;
573 if (!test_bit(WDM_IN_USE, &desc->flags))
574 mask |= POLLOUT | POLLWRNORM;
575 spin_unlock_irqrestore(&desc->iuspin, flags);
576
577 poll_wait(file, &desc->wait, wait);
578
579desc_out:
580 return mask;
581}
582
583static int wdm_open(struct inode *inode, struct file *file)
584{
585 int minor = iminor(inode);
586 int rv = -ENODEV;
587 struct usb_interface *intf;
588 struct wdm_device *desc;
589
590 mutex_lock(&wdm_mutex);
591 desc = wdm_find_device_by_minor(minor);
592 if (!desc)
593 goto out;
594
595 intf = desc->intf;
596 if (test_bit(WDM_DISCONNECTING, &desc->flags))
597 goto out;
598 file->private_data = desc;
599
600 rv = usb_autopm_get_interface(desc->intf);
601 if (rv < 0) {
602 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
603 goto out;
604 }
605
606 /* using write lock to protect desc->count */
607 mutex_lock(&desc->wlock);
608 if (!desc->count++) {
609 desc->werr = 0;
610 desc->rerr = 0;
611 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
612 if (rv < 0) {
613 desc->count--;
614 dev_err(&desc->intf->dev,
615 "Error submitting int urb - %d\n", rv);
616 rv = usb_translate_errors(rv);
617 }
618 } else {
619 rv = 0;
620 }
621 mutex_unlock(&desc->wlock);
622 if (desc->count == 1)
623 desc->manage_power(intf, 1);
624 usb_autopm_put_interface(desc->intf);
625out:
626 mutex_unlock(&wdm_mutex);
627 return rv;
628}
629
630static int wdm_release(struct inode *inode, struct file *file)
631{
632 struct wdm_device *desc = file->private_data;
633
634 mutex_lock(&wdm_mutex);
635
636 /* using write lock to protect desc->count */
637 mutex_lock(&desc->wlock);
638 desc->count--;
639 mutex_unlock(&desc->wlock);
640
641 if (!desc->count) {
642 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
643 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
644 kill_urbs(desc);
645 desc->manage_power(desc->intf, 0);
646 } else {
647 /* must avoid dev_printk here as desc->intf is invalid */
648 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
649 cleanup(desc);
650 }
651 }
652 mutex_unlock(&wdm_mutex);
653 return 0;
654}
655
656static const struct file_operations wdm_fops = {
657 .owner = THIS_MODULE,
658 .read = wdm_read,
659 .write = wdm_write,
660 .open = wdm_open,
661 .flush = wdm_flush,
662 .release = wdm_release,
663 .poll = wdm_poll,
664 .llseek = noop_llseek,
665};
666
667static struct usb_class_driver wdm_class = {
668 .name = "cdc-wdm%d",
669 .fops = &wdm_fops,
670 .minor_base = WDM_MINOR_BASE,
671};
672
673/* --- error handling --- */
674static void wdm_rxwork(struct work_struct *work)
675{
676 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
677 unsigned long flags;
678 int rv;
679
680 spin_lock_irqsave(&desc->iuspin, flags);
681 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
682 spin_unlock_irqrestore(&desc->iuspin, flags);
683 } else {
684 spin_unlock_irqrestore(&desc->iuspin, flags);
685 rv = usb_submit_urb(desc->response, GFP_KERNEL);
686 if (rv < 0 && rv != -EPERM) {
687 spin_lock_irqsave(&desc->iuspin, flags);
688 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
689 schedule_work(&desc->rxwork);
690 spin_unlock_irqrestore(&desc->iuspin, flags);
691 }
692 }
693}
694
695/* --- hotplug --- */
696
697static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
698 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
699{
700 int rv = -ENOMEM;
701 struct wdm_device *desc;
702
703 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
704 if (!desc)
705 goto out;
706 INIT_LIST_HEAD(&desc->device_list);
707 mutex_init(&desc->rlock);
708 mutex_init(&desc->wlock);
709 spin_lock_init(&desc->iuspin);
710 init_waitqueue_head(&desc->wait);
711 desc->wMaxCommand = bufsize;
712 /* this will be expanded and needed in hardware endianness */
713 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
714 desc->intf = intf;
715 INIT_WORK(&desc->rxwork, wdm_rxwork);
716
717 rv = -EINVAL;
718 if (!usb_endpoint_is_int_in(ep))
719 goto err;
720
721 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
722
723 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
724 if (!desc->orq)
725 goto err;
726 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
727 if (!desc->irq)
728 goto err;
729
730 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
731 if (!desc->validity)
732 goto err;
733
734 desc->response = usb_alloc_urb(0, GFP_KERNEL);
735 if (!desc->response)
736 goto err;
737
738 desc->command = usb_alloc_urb(0, GFP_KERNEL);
739 if (!desc->command)
740 goto err;
741
742 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
743 if (!desc->ubuf)
744 goto err;
745
746 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
747 if (!desc->sbuf)
748 goto err;
749
750 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
751 if (!desc->inbuf)
752 goto err;
753
754 usb_fill_int_urb(
755 desc->validity,
756 interface_to_usbdev(intf),
757 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
758 desc->sbuf,
759 desc->wMaxPacketSize,
760 wdm_int_callback,
761 desc,
762 ep->bInterval
763 );
764
765 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
766 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
767 desc->irq->wValue = 0;
768 desc->irq->wIndex = desc->inum;
769 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
770
771 usb_fill_control_urb(
772 desc->response,
773 interface_to_usbdev(intf),
774 /* using common endpoint 0 */
775 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
776 (unsigned char *)desc->irq,
777 desc->inbuf,
778 desc->wMaxCommand,
779 wdm_in_callback,
780 desc
781 );
782
783 desc->manage_power = manage_power;
784
785 spin_lock(&wdm_device_list_lock);
786 list_add(&desc->device_list, &wdm_device_list);
787 spin_unlock(&wdm_device_list_lock);
788
789 rv = usb_register_dev(intf, &wdm_class);
790 if (rv < 0)
791 goto err;
792 else
793 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
794out:
795 return rv;
796err:
797 spin_lock(&wdm_device_list_lock);
798 list_del(&desc->device_list);
799 spin_unlock(&wdm_device_list_lock);
800 cleanup(desc);
801 return rv;
802}
803
804static int wdm_manage_power(struct usb_interface *intf, int on)
805{
806 /* need autopm_get/put here to ensure the usbcore sees the new value */
807 int rv = usb_autopm_get_interface(intf);
808 if (rv < 0)
809 goto err;
810
811 intf->needs_remote_wakeup = on;
812 usb_autopm_put_interface(intf);
813err:
814 return rv;
815}
816
817static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
818{
819 int rv = -EINVAL;
820 struct usb_host_interface *iface;
821 struct usb_endpoint_descriptor *ep;
822 struct usb_cdc_dmm_desc *dmhd;
823 u8 *buffer = intf->altsetting->extra;
824 int buflen = intf->altsetting->extralen;
825 u16 maxcom = WDM_DEFAULT_BUFSIZE;
826
827 if (!buffer)
828 goto err;
829 while (buflen > 2) {
830 if (buffer[1] != USB_DT_CS_INTERFACE) {
831 dev_err(&intf->dev, "skipping garbage\n");
832 goto next_desc;
833 }
834
835 switch (buffer[2]) {
836 case USB_CDC_HEADER_TYPE:
837 break;
838 case USB_CDC_DMM_TYPE:
839 dmhd = (struct usb_cdc_dmm_desc *)buffer;
840 maxcom = le16_to_cpu(dmhd->wMaxCommand);
841 dev_dbg(&intf->dev,
842 "Finding maximum buffer length: %d", maxcom);
843 break;
844 default:
845 dev_err(&intf->dev,
846 "Ignoring extra header, type %d, length %d\n",
847 buffer[2], buffer[0]);
848 break;
849 }
850next_desc:
851 buflen -= buffer[0];
852 buffer += buffer[0];
853 }
854
855 iface = intf->cur_altsetting;
856 if (iface->desc.bNumEndpoints != 1)
857 goto err;
858 ep = &iface->endpoint[0].desc;
859
860 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
861
862err:
863 return rv;
864}
865
866/**
867 * usb_cdc_wdm_register - register a WDM subdriver
868 * @intf: usb interface the subdriver will associate with
869 * @ep: interrupt endpoint to monitor for notifications
870 * @bufsize: maximum message size to support for read/write
871 *
872 * Create WDM usb class character device and associate it with intf
873 * without binding, allowing another driver to manage the interface.
874 *
875 * The subdriver will manage the given interrupt endpoint exclusively
876 * and will issue control requests referring to the given intf. It
877 * will otherwise avoid interferring, and in particular not do
878 * usb_set_intfdata/usb_get_intfdata on intf.
879 *
880 * The return value is a pointer to the subdriver's struct usb_driver.
881 * The registering driver is responsible for calling this subdriver's
882 * disconnect, suspend, resume, pre_reset and post_reset methods from
883 * its own.
884 */
885struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
886 struct usb_endpoint_descriptor *ep,
887 int bufsize,
888 int (*manage_power)(struct usb_interface *, int))
889{
890 int rv = -EINVAL;
891
892 rv = wdm_create(intf, ep, bufsize, manage_power);
893 if (rv < 0)
894 goto err;
895
896 return &wdm_driver;
897err:
898 return ERR_PTR(rv);
899}
900EXPORT_SYMBOL(usb_cdc_wdm_register);
901
902static void wdm_disconnect(struct usb_interface *intf)
903{
904 struct wdm_device *desc;
905 unsigned long flags;
906
907 usb_deregister_dev(intf, &wdm_class);
908 desc = wdm_find_device(intf);
909 mutex_lock(&wdm_mutex);
910
911 /* the spinlock makes sure no new urbs are generated in the callbacks */
912 spin_lock_irqsave(&desc->iuspin, flags);
913 set_bit(WDM_DISCONNECTING, &desc->flags);
914 set_bit(WDM_READ, &desc->flags);
915 /* to terminate pending flushes */
916 clear_bit(WDM_IN_USE, &desc->flags);
917 spin_unlock_irqrestore(&desc->iuspin, flags);
918 wake_up_all(&desc->wait);
919 mutex_lock(&desc->rlock);
920 mutex_lock(&desc->wlock);
921 kill_urbs(desc);
922 cancel_work_sync(&desc->rxwork);
923 mutex_unlock(&desc->wlock);
924 mutex_unlock(&desc->rlock);
925
926 /* the desc->intf pointer used as list key is now invalid */
927 spin_lock(&wdm_device_list_lock);
928 list_del(&desc->device_list);
929 spin_unlock(&wdm_device_list_lock);
930
931 if (!desc->count)
932 cleanup(desc);
933 else
934 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
935 mutex_unlock(&wdm_mutex);
936}
937
938#ifdef CONFIG_PM
939static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
940{
941 struct wdm_device *desc = wdm_find_device(intf);
942 int rv = 0;
943
944 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
945
946 /* if this is an autosuspend the caller does the locking */
947 if (!PMSG_IS_AUTO(message)) {
948 mutex_lock(&desc->rlock);
949 mutex_lock(&desc->wlock);
950 }
951 spin_lock_irq(&desc->iuspin);
952
953 if (PMSG_IS_AUTO(message) &&
954 (test_bit(WDM_IN_USE, &desc->flags)
955 || test_bit(WDM_RESPONDING, &desc->flags))) {
956 spin_unlock_irq(&desc->iuspin);
957 rv = -EBUSY;
958 } else {
959
960 set_bit(WDM_SUSPENDING, &desc->flags);
961 spin_unlock_irq(&desc->iuspin);
962 /* callback submits work - order is essential */
963 kill_urbs(desc);
964 cancel_work_sync(&desc->rxwork);
965 }
966 if (!PMSG_IS_AUTO(message)) {
967 mutex_unlock(&desc->wlock);
968 mutex_unlock(&desc->rlock);
969 }
970
971 return rv;
972}
973#endif
974
975static int recover_from_urb_loss(struct wdm_device *desc)
976{
977 int rv = 0;
978
979 if (desc->count) {
980 rv = usb_submit_urb(desc->validity, GFP_NOIO);
981 if (rv < 0)
982 dev_err(&desc->intf->dev,
983 "Error resume submitting int urb - %d\n", rv);
984 }
985 return rv;
986}
987
988#ifdef CONFIG_PM
989static int wdm_resume(struct usb_interface *intf)
990{
991 struct wdm_device *desc = wdm_find_device(intf);
992 int rv;
993
994 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
995
996 clear_bit(WDM_SUSPENDING, &desc->flags);
997 rv = recover_from_urb_loss(desc);
998
999 return rv;
1000}
1001#endif
1002
1003static int wdm_pre_reset(struct usb_interface *intf)
1004{
1005 struct wdm_device *desc = wdm_find_device(intf);
1006
1007 /*
1008 * we notify everybody using poll of
1009 * an exceptional situation
1010 * must be done before recovery lest a spontaneous
1011 * message from the device is lost
1012 */
1013 spin_lock_irq(&desc->iuspin);
1014 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1015 set_bit(WDM_READ, &desc->flags); /* unblock read */
1016 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1017 desc->rerr = -EINTR;
1018 spin_unlock_irq(&desc->iuspin);
1019 wake_up_all(&desc->wait);
1020 mutex_lock(&desc->rlock);
1021 mutex_lock(&desc->wlock);
1022 kill_urbs(desc);
1023 cancel_work_sync(&desc->rxwork);
1024 return 0;
1025}
1026
1027static int wdm_post_reset(struct usb_interface *intf)
1028{
1029 struct wdm_device *desc = wdm_find_device(intf);
1030 int rv;
1031
1032 clear_bit(WDM_RESETTING, &desc->flags);
1033 rv = recover_from_urb_loss(desc);
1034 mutex_unlock(&desc->wlock);
1035 mutex_unlock(&desc->rlock);
1036 return 0;
1037}
1038
1039static struct usb_driver wdm_driver = {
1040 .name = "cdc_wdm",
1041 .probe = wdm_probe,
1042 .disconnect = wdm_disconnect,
1043#ifdef CONFIG_PM
1044 .suspend = wdm_suspend,
1045 .resume = wdm_resume,
1046 .reset_resume = wdm_resume,
1047#endif
1048 .pre_reset = wdm_pre_reset,
1049 .post_reset = wdm_post_reset,
1050 .id_table = wdm_ids,
1051 .supports_autosuspend = 1,
1052 .disable_hub_initiated_lpm = 1,
1053};
1054
1055module_usb_driver(wdm_driver);
1056
1057MODULE_AUTHOR(DRIVER_AUTHOR);
1058MODULE_DESCRIPTION(DRIVER_DESC);
1059MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * cdc-wdm.c
4 *
5 * This driver supports USB CDC WCM Device Management.
6 *
7 * Copyright (c) 2007-2009 Oliver Neukum
8 *
9 * Some code taken from cdc-acm.c
10 *
11 * Released under the GPLv2.
12 *
13 * Many thanks to Carl Nordbeck
14 */
15#include <linux/kernel.h>
16#include <linux/errno.h>
17#include <linux/ioctl.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/mutex.h>
21#include <linux/uaccess.h>
22#include <linux/bitops.h>
23#include <linux/poll.h>
24#include <linux/usb.h>
25#include <linux/usb/cdc.h>
26#include <asm/byteorder.h>
27#include <asm/unaligned.h>
28#include <linux/usb/cdc-wdm.h>
29
30#define DRIVER_AUTHOR "Oliver Neukum"
31#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
32
33static const struct usb_device_id wdm_ids[] = {
34 {
35 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
36 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
37 .bInterfaceClass = USB_CLASS_COMM,
38 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
39 },
40 { }
41};
42
43MODULE_DEVICE_TABLE (usb, wdm_ids);
44
45#define WDM_MINOR_BASE 176
46
47
48#define WDM_IN_USE 1
49#define WDM_DISCONNECTING 2
50#define WDM_RESULT 3
51#define WDM_READ 4
52#define WDM_INT_STALL 5
53#define WDM_POLL_RUNNING 6
54#define WDM_RESPONDING 7
55#define WDM_SUSPENDING 8
56#define WDM_RESETTING 9
57#define WDM_OVERFLOW 10
58
59#define WDM_MAX 16
60
61/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
62#define WDM_DEFAULT_BUFSIZE 256
63
64static DEFINE_MUTEX(wdm_mutex);
65static DEFINE_SPINLOCK(wdm_device_list_lock);
66static LIST_HEAD(wdm_device_list);
67
68/* --- method tables --- */
69
70struct wdm_device {
71 u8 *inbuf; /* buffer for response */
72 u8 *outbuf; /* buffer for command */
73 u8 *sbuf; /* buffer for status */
74 u8 *ubuf; /* buffer for copy to user space */
75
76 struct urb *command;
77 struct urb *response;
78 struct urb *validity;
79 struct usb_interface *intf;
80 struct usb_ctrlrequest *orq;
81 struct usb_ctrlrequest *irq;
82 spinlock_t iuspin;
83
84 unsigned long flags;
85 u16 bufsize;
86 u16 wMaxCommand;
87 u16 wMaxPacketSize;
88 __le16 inum;
89 int reslength;
90 int length;
91 int read;
92 int count;
93 dma_addr_t shandle;
94 dma_addr_t ihandle;
95 struct mutex wlock;
96 struct mutex rlock;
97 wait_queue_head_t wait;
98 struct work_struct rxwork;
99 int werr;
100 int rerr;
101 int resp_count;
102
103 struct list_head device_list;
104 int (*manage_power)(struct usb_interface *, int);
105};
106
107static struct usb_driver wdm_driver;
108
109/* return intfdata if we own the interface, else look up intf in the list */
110static struct wdm_device *wdm_find_device(struct usb_interface *intf)
111{
112 struct wdm_device *desc;
113
114 spin_lock(&wdm_device_list_lock);
115 list_for_each_entry(desc, &wdm_device_list, device_list)
116 if (desc->intf == intf)
117 goto found;
118 desc = NULL;
119found:
120 spin_unlock(&wdm_device_list_lock);
121
122 return desc;
123}
124
125static struct wdm_device *wdm_find_device_by_minor(int minor)
126{
127 struct wdm_device *desc;
128
129 spin_lock(&wdm_device_list_lock);
130 list_for_each_entry(desc, &wdm_device_list, device_list)
131 if (desc->intf->minor == minor)
132 goto found;
133 desc = NULL;
134found:
135 spin_unlock(&wdm_device_list_lock);
136
137 return desc;
138}
139
140/* --- callbacks --- */
141static void wdm_out_callback(struct urb *urb)
142{
143 struct wdm_device *desc;
144 desc = urb->context;
145 spin_lock(&desc->iuspin);
146 desc->werr = urb->status;
147 spin_unlock(&desc->iuspin);
148 kfree(desc->outbuf);
149 desc->outbuf = NULL;
150 clear_bit(WDM_IN_USE, &desc->flags);
151 wake_up(&desc->wait);
152}
153
154/* forward declaration */
155static int service_outstanding_interrupt(struct wdm_device *desc);
156
157static void wdm_in_callback(struct urb *urb)
158{
159 struct wdm_device *desc = urb->context;
160 int status = urb->status;
161 int length = urb->actual_length;
162
163 spin_lock(&desc->iuspin);
164 clear_bit(WDM_RESPONDING, &desc->flags);
165
166 if (status) {
167 switch (status) {
168 case -ENOENT:
169 dev_dbg(&desc->intf->dev,
170 "nonzero urb status received: -ENOENT\n");
171 goto skip_error;
172 case -ECONNRESET:
173 dev_dbg(&desc->intf->dev,
174 "nonzero urb status received: -ECONNRESET\n");
175 goto skip_error;
176 case -ESHUTDOWN:
177 dev_dbg(&desc->intf->dev,
178 "nonzero urb status received: -ESHUTDOWN\n");
179 goto skip_error;
180 case -EPIPE:
181 dev_err(&desc->intf->dev,
182 "nonzero urb status received: -EPIPE\n");
183 break;
184 default:
185 dev_err(&desc->intf->dev,
186 "Unexpected error %d\n", status);
187 break;
188 }
189 }
190
191 /*
192 * only set a new error if there is no previous error.
193 * Errors are only cleared during read/open
194 * Avoid propagating -EPIPE (stall) to userspace since it is
195 * better handled as an empty read
196 */
197 if (desc->rerr == 0 && status != -EPIPE)
198 desc->rerr = status;
199
200 if (length + desc->length > desc->wMaxCommand) {
201 /* The buffer would overflow */
202 set_bit(WDM_OVERFLOW, &desc->flags);
203 } else {
204 /* we may already be in overflow */
205 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
206 memmove(desc->ubuf + desc->length, desc->inbuf, length);
207 desc->length += length;
208 desc->reslength = length;
209 }
210 }
211skip_error:
212 set_bit(WDM_READ, &desc->flags);
213 wake_up(&desc->wait);
214
215 if (desc->rerr) {
216 /*
217 * Since there was an error, userspace may decide to not read
218 * any data after poll'ing.
219 * We should respond to further attempts from the device to send
220 * data, so that we can get unstuck.
221 */
222 service_outstanding_interrupt(desc);
223 }
224
225 spin_unlock(&desc->iuspin);
226}
227
228static void wdm_int_callback(struct urb *urb)
229{
230 int rv = 0;
231 int responding;
232 int status = urb->status;
233 struct wdm_device *desc;
234 struct usb_cdc_notification *dr;
235
236 desc = urb->context;
237 dr = (struct usb_cdc_notification *)desc->sbuf;
238
239 if (status) {
240 switch (status) {
241 case -ESHUTDOWN:
242 case -ENOENT:
243 case -ECONNRESET:
244 return; /* unplug */
245 case -EPIPE:
246 set_bit(WDM_INT_STALL, &desc->flags);
247 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
248 goto sw; /* halt is cleared in work */
249 default:
250 dev_err(&desc->intf->dev,
251 "nonzero urb status received: %d\n", status);
252 break;
253 }
254 }
255
256 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
257 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
258 urb->actual_length);
259 goto exit;
260 }
261
262 switch (dr->bNotificationType) {
263 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
264 dev_dbg(&desc->intf->dev,
265 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
266 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
267 break;
268
269 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
270
271 dev_dbg(&desc->intf->dev,
272 "NOTIFY_NETWORK_CONNECTION %s network\n",
273 dr->wValue ? "connected to" : "disconnected from");
274 goto exit;
275 case USB_CDC_NOTIFY_SPEED_CHANGE:
276 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
277 urb->actual_length);
278 goto exit;
279 default:
280 clear_bit(WDM_POLL_RUNNING, &desc->flags);
281 dev_err(&desc->intf->dev,
282 "unknown notification %d received: index %d len %d\n",
283 dr->bNotificationType,
284 le16_to_cpu(dr->wIndex),
285 le16_to_cpu(dr->wLength));
286 goto exit;
287 }
288
289 spin_lock(&desc->iuspin);
290 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
291 if (!desc->resp_count++ && !responding
292 && !test_bit(WDM_DISCONNECTING, &desc->flags)
293 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
294 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
295 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
296 }
297 spin_unlock(&desc->iuspin);
298 if (rv < 0) {
299 clear_bit(WDM_RESPONDING, &desc->flags);
300 if (rv == -EPERM)
301 return;
302 if (rv == -ENOMEM) {
303sw:
304 rv = schedule_work(&desc->rxwork);
305 if (rv)
306 dev_err(&desc->intf->dev,
307 "Cannot schedule work\n");
308 }
309 }
310exit:
311 rv = usb_submit_urb(urb, GFP_ATOMIC);
312 if (rv)
313 dev_err(&desc->intf->dev,
314 "%s - usb_submit_urb failed with result %d\n",
315 __func__, rv);
316
317}
318
319static void kill_urbs(struct wdm_device *desc)
320{
321 /* the order here is essential */
322 usb_kill_urb(desc->command);
323 usb_kill_urb(desc->validity);
324 usb_kill_urb(desc->response);
325}
326
327static void free_urbs(struct wdm_device *desc)
328{
329 usb_free_urb(desc->validity);
330 usb_free_urb(desc->response);
331 usb_free_urb(desc->command);
332}
333
334static void cleanup(struct wdm_device *desc)
335{
336 kfree(desc->sbuf);
337 kfree(desc->inbuf);
338 kfree(desc->orq);
339 kfree(desc->irq);
340 kfree(desc->ubuf);
341 free_urbs(desc);
342 kfree(desc);
343}
344
345static ssize_t wdm_write
346(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
347{
348 u8 *buf;
349 int rv = -EMSGSIZE, r, we;
350 struct wdm_device *desc = file->private_data;
351 struct usb_ctrlrequest *req;
352
353 if (count > desc->wMaxCommand)
354 count = desc->wMaxCommand;
355
356 spin_lock_irq(&desc->iuspin);
357 we = desc->werr;
358 desc->werr = 0;
359 spin_unlock_irq(&desc->iuspin);
360 if (we < 0)
361 return usb_translate_errors(we);
362
363 buf = memdup_user(buffer, count);
364 if (IS_ERR(buf))
365 return PTR_ERR(buf);
366
367 /* concurrent writes and disconnect */
368 r = mutex_lock_interruptible(&desc->wlock);
369 rv = -ERESTARTSYS;
370 if (r)
371 goto out_free_mem;
372
373 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
374 rv = -ENODEV;
375 goto out_free_mem_lock;
376 }
377
378 r = usb_autopm_get_interface(desc->intf);
379 if (r < 0) {
380 rv = usb_translate_errors(r);
381 goto out_free_mem_lock;
382 }
383
384 if (!(file->f_flags & O_NONBLOCK))
385 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
386 &desc->flags));
387 else
388 if (test_bit(WDM_IN_USE, &desc->flags))
389 r = -EAGAIN;
390
391 if (test_bit(WDM_RESETTING, &desc->flags))
392 r = -EIO;
393
394 if (r < 0) {
395 rv = r;
396 goto out_free_mem_pm;
397 }
398
399 req = desc->orq;
400 usb_fill_control_urb(
401 desc->command,
402 interface_to_usbdev(desc->intf),
403 /* using common endpoint 0 */
404 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
405 (unsigned char *)req,
406 buf,
407 count,
408 wdm_out_callback,
409 desc
410 );
411
412 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
413 USB_RECIP_INTERFACE);
414 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
415 req->wValue = 0;
416 req->wIndex = desc->inum; /* already converted */
417 req->wLength = cpu_to_le16(count);
418 set_bit(WDM_IN_USE, &desc->flags);
419 desc->outbuf = buf;
420
421 rv = usb_submit_urb(desc->command, GFP_KERNEL);
422 if (rv < 0) {
423 desc->outbuf = NULL;
424 clear_bit(WDM_IN_USE, &desc->flags);
425 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
426 rv = usb_translate_errors(rv);
427 goto out_free_mem_pm;
428 } else {
429 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
430 le16_to_cpu(req->wIndex));
431 }
432
433 usb_autopm_put_interface(desc->intf);
434 mutex_unlock(&desc->wlock);
435 return count;
436
437out_free_mem_pm:
438 usb_autopm_put_interface(desc->intf);
439out_free_mem_lock:
440 mutex_unlock(&desc->wlock);
441out_free_mem:
442 kfree(buf);
443 return rv;
444}
445
446/*
447 * Submit the read urb if resp_count is non-zero.
448 *
449 * Called with desc->iuspin locked
450 */
451static int service_outstanding_interrupt(struct wdm_device *desc)
452{
453 int rv = 0;
454
455 /* submit read urb only if the device is waiting for it */
456 if (!desc->resp_count || !--desc->resp_count)
457 goto out;
458
459 set_bit(WDM_RESPONDING, &desc->flags);
460 spin_unlock_irq(&desc->iuspin);
461 rv = usb_submit_urb(desc->response, GFP_KERNEL);
462 spin_lock_irq(&desc->iuspin);
463 if (rv) {
464 dev_err(&desc->intf->dev,
465 "usb_submit_urb failed with result %d\n", rv);
466
467 /* make sure the next notification trigger a submit */
468 clear_bit(WDM_RESPONDING, &desc->flags);
469 desc->resp_count = 0;
470 }
471out:
472 return rv;
473}
474
475static ssize_t wdm_read
476(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
477{
478 int rv, cntr;
479 int i = 0;
480 struct wdm_device *desc = file->private_data;
481
482
483 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
484 if (rv < 0)
485 return -ERESTARTSYS;
486
487 cntr = READ_ONCE(desc->length);
488 if (cntr == 0) {
489 desc->read = 0;
490retry:
491 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
492 rv = -ENODEV;
493 goto err;
494 }
495 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
496 clear_bit(WDM_OVERFLOW, &desc->flags);
497 rv = -ENOBUFS;
498 goto err;
499 }
500 i++;
501 if (file->f_flags & O_NONBLOCK) {
502 if (!test_bit(WDM_READ, &desc->flags)) {
503 rv = -EAGAIN;
504 goto err;
505 }
506 rv = 0;
507 } else {
508 rv = wait_event_interruptible(desc->wait,
509 test_bit(WDM_READ, &desc->flags));
510 }
511
512 /* may have happened while we slept */
513 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
514 rv = -ENODEV;
515 goto err;
516 }
517 if (test_bit(WDM_RESETTING, &desc->flags)) {
518 rv = -EIO;
519 goto err;
520 }
521 usb_mark_last_busy(interface_to_usbdev(desc->intf));
522 if (rv < 0) {
523 rv = -ERESTARTSYS;
524 goto err;
525 }
526
527 spin_lock_irq(&desc->iuspin);
528
529 if (desc->rerr) { /* read completed, error happened */
530 rv = usb_translate_errors(desc->rerr);
531 desc->rerr = 0;
532 spin_unlock_irq(&desc->iuspin);
533 goto err;
534 }
535 /*
536 * recheck whether we've lost the race
537 * against the completion handler
538 */
539 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
540 spin_unlock_irq(&desc->iuspin);
541 goto retry;
542 }
543
544 if (!desc->reslength) { /* zero length read */
545 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
546 clear_bit(WDM_READ, &desc->flags);
547 rv = service_outstanding_interrupt(desc);
548 spin_unlock_irq(&desc->iuspin);
549 if (rv < 0)
550 goto err;
551 goto retry;
552 }
553 cntr = desc->length;
554 spin_unlock_irq(&desc->iuspin);
555 }
556
557 if (cntr > count)
558 cntr = count;
559 rv = copy_to_user(buffer, desc->ubuf, cntr);
560 if (rv > 0) {
561 rv = -EFAULT;
562 goto err;
563 }
564
565 spin_lock_irq(&desc->iuspin);
566
567 for (i = 0; i < desc->length - cntr; i++)
568 desc->ubuf[i] = desc->ubuf[i + cntr];
569
570 desc->length -= cntr;
571 /* in case we had outstanding data */
572 if (!desc->length) {
573 clear_bit(WDM_READ, &desc->flags);
574 service_outstanding_interrupt(desc);
575 }
576 spin_unlock_irq(&desc->iuspin);
577 rv = cntr;
578
579err:
580 mutex_unlock(&desc->rlock);
581 return rv;
582}
583
584static int wdm_flush(struct file *file, fl_owner_t id)
585{
586 struct wdm_device *desc = file->private_data;
587
588 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
589
590 /* cannot dereference desc->intf if WDM_DISCONNECTING */
591 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
592 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
593 desc->werr);
594
595 return usb_translate_errors(desc->werr);
596}
597
598static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
599{
600 struct wdm_device *desc = file->private_data;
601 unsigned long flags;
602 __poll_t mask = 0;
603
604 spin_lock_irqsave(&desc->iuspin, flags);
605 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
606 mask = EPOLLHUP | EPOLLERR;
607 spin_unlock_irqrestore(&desc->iuspin, flags);
608 goto desc_out;
609 }
610 if (test_bit(WDM_READ, &desc->flags))
611 mask = EPOLLIN | EPOLLRDNORM;
612 if (desc->rerr || desc->werr)
613 mask |= EPOLLERR;
614 if (!test_bit(WDM_IN_USE, &desc->flags))
615 mask |= EPOLLOUT | EPOLLWRNORM;
616 spin_unlock_irqrestore(&desc->iuspin, flags);
617
618 poll_wait(file, &desc->wait, wait);
619
620desc_out:
621 return mask;
622}
623
624static int wdm_open(struct inode *inode, struct file *file)
625{
626 int minor = iminor(inode);
627 int rv = -ENODEV;
628 struct usb_interface *intf;
629 struct wdm_device *desc;
630
631 mutex_lock(&wdm_mutex);
632 desc = wdm_find_device_by_minor(minor);
633 if (!desc)
634 goto out;
635
636 intf = desc->intf;
637 if (test_bit(WDM_DISCONNECTING, &desc->flags))
638 goto out;
639 file->private_data = desc;
640
641 rv = usb_autopm_get_interface(desc->intf);
642 if (rv < 0) {
643 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
644 goto out;
645 }
646
647 /* using write lock to protect desc->count */
648 mutex_lock(&desc->wlock);
649 if (!desc->count++) {
650 desc->werr = 0;
651 desc->rerr = 0;
652 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
653 if (rv < 0) {
654 desc->count--;
655 dev_err(&desc->intf->dev,
656 "Error submitting int urb - %d\n", rv);
657 rv = usb_translate_errors(rv);
658 }
659 } else {
660 rv = 0;
661 }
662 mutex_unlock(&desc->wlock);
663 if (desc->count == 1)
664 desc->manage_power(intf, 1);
665 usb_autopm_put_interface(desc->intf);
666out:
667 mutex_unlock(&wdm_mutex);
668 return rv;
669}
670
671static int wdm_release(struct inode *inode, struct file *file)
672{
673 struct wdm_device *desc = file->private_data;
674
675 mutex_lock(&wdm_mutex);
676
677 /* using write lock to protect desc->count */
678 mutex_lock(&desc->wlock);
679 desc->count--;
680 mutex_unlock(&desc->wlock);
681
682 if (!desc->count) {
683 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
684 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
685 kill_urbs(desc);
686 spin_lock_irq(&desc->iuspin);
687 desc->resp_count = 0;
688 spin_unlock_irq(&desc->iuspin);
689 desc->manage_power(desc->intf, 0);
690 } else {
691 /* must avoid dev_printk here as desc->intf is invalid */
692 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
693 cleanup(desc);
694 }
695 }
696 mutex_unlock(&wdm_mutex);
697 return 0;
698}
699
700static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
701{
702 struct wdm_device *desc = file->private_data;
703 int rv = 0;
704
705 switch (cmd) {
706 case IOCTL_WDM_MAX_COMMAND:
707 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
708 rv = -EFAULT;
709 break;
710 default:
711 rv = -ENOTTY;
712 }
713 return rv;
714}
715
716static const struct file_operations wdm_fops = {
717 .owner = THIS_MODULE,
718 .read = wdm_read,
719 .write = wdm_write,
720 .open = wdm_open,
721 .flush = wdm_flush,
722 .release = wdm_release,
723 .poll = wdm_poll,
724 .unlocked_ioctl = wdm_ioctl,
725 .compat_ioctl = wdm_ioctl,
726 .llseek = noop_llseek,
727};
728
729static struct usb_class_driver wdm_class = {
730 .name = "cdc-wdm%d",
731 .fops = &wdm_fops,
732 .minor_base = WDM_MINOR_BASE,
733};
734
735/* --- error handling --- */
736static void wdm_rxwork(struct work_struct *work)
737{
738 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
739 unsigned long flags;
740 int rv = 0;
741 int responding;
742
743 spin_lock_irqsave(&desc->iuspin, flags);
744 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
745 spin_unlock_irqrestore(&desc->iuspin, flags);
746 } else {
747 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
748 spin_unlock_irqrestore(&desc->iuspin, flags);
749 if (!responding)
750 rv = usb_submit_urb(desc->response, GFP_KERNEL);
751 if (rv < 0 && rv != -EPERM) {
752 spin_lock_irqsave(&desc->iuspin, flags);
753 clear_bit(WDM_RESPONDING, &desc->flags);
754 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
755 schedule_work(&desc->rxwork);
756 spin_unlock_irqrestore(&desc->iuspin, flags);
757 }
758 }
759}
760
761/* --- hotplug --- */
762
763static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
764 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
765{
766 int rv = -ENOMEM;
767 struct wdm_device *desc;
768
769 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
770 if (!desc)
771 goto out;
772 INIT_LIST_HEAD(&desc->device_list);
773 mutex_init(&desc->rlock);
774 mutex_init(&desc->wlock);
775 spin_lock_init(&desc->iuspin);
776 init_waitqueue_head(&desc->wait);
777 desc->wMaxCommand = bufsize;
778 /* this will be expanded and needed in hardware endianness */
779 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
780 desc->intf = intf;
781 INIT_WORK(&desc->rxwork, wdm_rxwork);
782
783 rv = -EINVAL;
784 if (!usb_endpoint_is_int_in(ep))
785 goto err;
786
787 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
788
789 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
790 if (!desc->orq)
791 goto err;
792 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
793 if (!desc->irq)
794 goto err;
795
796 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
797 if (!desc->validity)
798 goto err;
799
800 desc->response = usb_alloc_urb(0, GFP_KERNEL);
801 if (!desc->response)
802 goto err;
803
804 desc->command = usb_alloc_urb(0, GFP_KERNEL);
805 if (!desc->command)
806 goto err;
807
808 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
809 if (!desc->ubuf)
810 goto err;
811
812 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
813 if (!desc->sbuf)
814 goto err;
815
816 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
817 if (!desc->inbuf)
818 goto err;
819
820 usb_fill_int_urb(
821 desc->validity,
822 interface_to_usbdev(intf),
823 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
824 desc->sbuf,
825 desc->wMaxPacketSize,
826 wdm_int_callback,
827 desc,
828 ep->bInterval
829 );
830
831 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
832 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
833 desc->irq->wValue = 0;
834 desc->irq->wIndex = desc->inum; /* already converted */
835 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
836
837 usb_fill_control_urb(
838 desc->response,
839 interface_to_usbdev(intf),
840 /* using common endpoint 0 */
841 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
842 (unsigned char *)desc->irq,
843 desc->inbuf,
844 desc->wMaxCommand,
845 wdm_in_callback,
846 desc
847 );
848
849 desc->manage_power = manage_power;
850
851 spin_lock(&wdm_device_list_lock);
852 list_add(&desc->device_list, &wdm_device_list);
853 spin_unlock(&wdm_device_list_lock);
854
855 rv = usb_register_dev(intf, &wdm_class);
856 if (rv < 0)
857 goto err;
858 else
859 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
860out:
861 return rv;
862err:
863 spin_lock(&wdm_device_list_lock);
864 list_del(&desc->device_list);
865 spin_unlock(&wdm_device_list_lock);
866 cleanup(desc);
867 return rv;
868}
869
870static int wdm_manage_power(struct usb_interface *intf, int on)
871{
872 /* need autopm_get/put here to ensure the usbcore sees the new value */
873 int rv = usb_autopm_get_interface(intf);
874
875 intf->needs_remote_wakeup = on;
876 if (!rv)
877 usb_autopm_put_interface(intf);
878 return 0;
879}
880
881static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
882{
883 int rv = -EINVAL;
884 struct usb_host_interface *iface;
885 struct usb_endpoint_descriptor *ep;
886 struct usb_cdc_parsed_header hdr;
887 u8 *buffer = intf->altsetting->extra;
888 int buflen = intf->altsetting->extralen;
889 u16 maxcom = WDM_DEFAULT_BUFSIZE;
890
891 if (!buffer)
892 goto err;
893
894 cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
895
896 if (hdr.usb_cdc_dmm_desc)
897 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
898
899 iface = intf->cur_altsetting;
900 if (iface->desc.bNumEndpoints != 1)
901 goto err;
902 ep = &iface->endpoint[0].desc;
903
904 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
905
906err:
907 return rv;
908}
909
910/**
911 * usb_cdc_wdm_register - register a WDM subdriver
912 * @intf: usb interface the subdriver will associate with
913 * @ep: interrupt endpoint to monitor for notifications
914 * @bufsize: maximum message size to support for read/write
915 *
916 * Create WDM usb class character device and associate it with intf
917 * without binding, allowing another driver to manage the interface.
918 *
919 * The subdriver will manage the given interrupt endpoint exclusively
920 * and will issue control requests referring to the given intf. It
921 * will otherwise avoid interferring, and in particular not do
922 * usb_set_intfdata/usb_get_intfdata on intf.
923 *
924 * The return value is a pointer to the subdriver's struct usb_driver.
925 * The registering driver is responsible for calling this subdriver's
926 * disconnect, suspend, resume, pre_reset and post_reset methods from
927 * its own.
928 */
929struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
930 struct usb_endpoint_descriptor *ep,
931 int bufsize,
932 int (*manage_power)(struct usb_interface *, int))
933{
934 int rv = -EINVAL;
935
936 rv = wdm_create(intf, ep, bufsize, manage_power);
937 if (rv < 0)
938 goto err;
939
940 return &wdm_driver;
941err:
942 return ERR_PTR(rv);
943}
944EXPORT_SYMBOL(usb_cdc_wdm_register);
945
946static void wdm_disconnect(struct usb_interface *intf)
947{
948 struct wdm_device *desc;
949 unsigned long flags;
950
951 usb_deregister_dev(intf, &wdm_class);
952 desc = wdm_find_device(intf);
953 mutex_lock(&wdm_mutex);
954
955 /* the spinlock makes sure no new urbs are generated in the callbacks */
956 spin_lock_irqsave(&desc->iuspin, flags);
957 set_bit(WDM_DISCONNECTING, &desc->flags);
958 set_bit(WDM_READ, &desc->flags);
959 /* to terminate pending flushes */
960 clear_bit(WDM_IN_USE, &desc->flags);
961 spin_unlock_irqrestore(&desc->iuspin, flags);
962 wake_up_all(&desc->wait);
963 mutex_lock(&desc->rlock);
964 mutex_lock(&desc->wlock);
965 kill_urbs(desc);
966 cancel_work_sync(&desc->rxwork);
967 mutex_unlock(&desc->wlock);
968 mutex_unlock(&desc->rlock);
969
970 /* the desc->intf pointer used as list key is now invalid */
971 spin_lock(&wdm_device_list_lock);
972 list_del(&desc->device_list);
973 spin_unlock(&wdm_device_list_lock);
974
975 if (!desc->count)
976 cleanup(desc);
977 else
978 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
979 mutex_unlock(&wdm_mutex);
980}
981
982#ifdef CONFIG_PM
983static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
984{
985 struct wdm_device *desc = wdm_find_device(intf);
986 int rv = 0;
987
988 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
989
990 /* if this is an autosuspend the caller does the locking */
991 if (!PMSG_IS_AUTO(message)) {
992 mutex_lock(&desc->rlock);
993 mutex_lock(&desc->wlock);
994 }
995 spin_lock_irq(&desc->iuspin);
996
997 if (PMSG_IS_AUTO(message) &&
998 (test_bit(WDM_IN_USE, &desc->flags)
999 || test_bit(WDM_RESPONDING, &desc->flags))) {
1000 spin_unlock_irq(&desc->iuspin);
1001 rv = -EBUSY;
1002 } else {
1003
1004 set_bit(WDM_SUSPENDING, &desc->flags);
1005 spin_unlock_irq(&desc->iuspin);
1006 /* callback submits work - order is essential */
1007 kill_urbs(desc);
1008 cancel_work_sync(&desc->rxwork);
1009 }
1010 if (!PMSG_IS_AUTO(message)) {
1011 mutex_unlock(&desc->wlock);
1012 mutex_unlock(&desc->rlock);
1013 }
1014
1015 return rv;
1016}
1017#endif
1018
1019static int recover_from_urb_loss(struct wdm_device *desc)
1020{
1021 int rv = 0;
1022
1023 if (desc->count) {
1024 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1025 if (rv < 0)
1026 dev_err(&desc->intf->dev,
1027 "Error resume submitting int urb - %d\n", rv);
1028 }
1029 return rv;
1030}
1031
1032#ifdef CONFIG_PM
1033static int wdm_resume(struct usb_interface *intf)
1034{
1035 struct wdm_device *desc = wdm_find_device(intf);
1036 int rv;
1037
1038 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1039
1040 clear_bit(WDM_SUSPENDING, &desc->flags);
1041 rv = recover_from_urb_loss(desc);
1042
1043 return rv;
1044}
1045#endif
1046
1047static int wdm_pre_reset(struct usb_interface *intf)
1048{
1049 struct wdm_device *desc = wdm_find_device(intf);
1050
1051 /*
1052 * we notify everybody using poll of
1053 * an exceptional situation
1054 * must be done before recovery lest a spontaneous
1055 * message from the device is lost
1056 */
1057 spin_lock_irq(&desc->iuspin);
1058 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1059 set_bit(WDM_READ, &desc->flags); /* unblock read */
1060 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1061 desc->rerr = -EINTR;
1062 spin_unlock_irq(&desc->iuspin);
1063 wake_up_all(&desc->wait);
1064 mutex_lock(&desc->rlock);
1065 mutex_lock(&desc->wlock);
1066 kill_urbs(desc);
1067 cancel_work_sync(&desc->rxwork);
1068 return 0;
1069}
1070
1071static int wdm_post_reset(struct usb_interface *intf)
1072{
1073 struct wdm_device *desc = wdm_find_device(intf);
1074 int rv;
1075
1076 clear_bit(WDM_OVERFLOW, &desc->flags);
1077 clear_bit(WDM_RESETTING, &desc->flags);
1078 rv = recover_from_urb_loss(desc);
1079 mutex_unlock(&desc->wlock);
1080 mutex_unlock(&desc->rlock);
1081 return 0;
1082}
1083
1084static struct usb_driver wdm_driver = {
1085 .name = "cdc_wdm",
1086 .probe = wdm_probe,
1087 .disconnect = wdm_disconnect,
1088#ifdef CONFIG_PM
1089 .suspend = wdm_suspend,
1090 .resume = wdm_resume,
1091 .reset_resume = wdm_resume,
1092#endif
1093 .pre_reset = wdm_pre_reset,
1094 .post_reset = wdm_post_reset,
1095 .id_table = wdm_ids,
1096 .supports_autosuspend = 1,
1097 .disable_hub_initiated_lpm = 1,
1098};
1099
1100module_usb_driver(wdm_driver);
1101
1102MODULE_AUTHOR(DRIVER_AUTHOR);
1103MODULE_DESCRIPTION(DRIVER_DESC);
1104MODULE_LICENSE("GPL");